Interpretive Summary: Water resources are a global concern as population grows and the need for water supplies expands. Watershed runoff and erosion models, such as the Kinematic Runoff and Erosion Model (KINEROS2) and the Soil and Water Assessment Tool (SWAT), are used to assess land use and climate-change impacts on water yield and quality. When these models are incorporated into a geographic information system (GIS) tool such as the Automated Geospatial Watershed Assessment Tool (AGWA), model inputs are easier to obtain, and the models become more accessible to a wider range of users. Developed by the USDA-ARS Southwest Watershed Research Center (www.tucson.ars.ag.gov/agwa), AGWA was originally designed to use the State Soil Geographic (STATSGO) and Soil Survey Geographic (SSURGO) databases, which are available only for the United States. The latest version of AGWA (1.4x) is able to use the internationally available Food and Agriculture Organization of the United Nations (FAO) digital soil map of the world. This reduces difficulties associated with different classification schemes on either side of a country border, making it easy to run hydrologic simulations for watersheds that cross country boundaries. This will allow AGWA and both models to be applied world-wide wherever the other required input data are available.

Technical Abstract:
The Automated Geospatial Watershed Assessment Tool (AGWA), a GIS-based hydrologic modeling tool available as an extension for ArcView 3.x from the USDA-ARS Southwest Watershed Research Center (www.tucson.ars.ag.gov/agwa) is designed to facilitate the assessment of land-use and climate-change impacts on water yield and quality at multiple scales. It parameterizes two watershed runoff and erosion models, the Kinematic Runoff and Erosion Model (KINEROS2) and the Soil and Water Assessment Tool (SWAT), using readily available topographic, soils, and land-cover data. AGWA was originally designed to obtain hydrologic parameters from the State Soil Geographic (STATSGO) and Soil Survey Geographic (SSURGO) databases, which are only available for the United States. The latest version of AGWA (1.4x) has incorporated the ability to derive inputs from the internationally available Food and Agriculture Organization of the United Nations (FAO) digital soil map of the world. The ability to use FAO soils in AGWA facilitates the analysis of trans-boundary watersheds by avoiding difficulties associated with different classification schemes on either side of the border. The methodology used to translate information from the FAO soils dataset and other sources into input parameters for hydrologic models will be presented, along with a comparison of model results using the FAO, SSURGO and STATSGO soils datasets.